Orbital lathe



W. F. GROENE Dec. 6; 1938.

ORBITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet l INYENTOR. WILL/RM Ff GROENE ATTORNEY.

Dec. 6, 1938. w. F. GROENE 2,133,954

ORBITAL LATHE Filed Jan 26, 1937 15 Sheets-Sheet 2 'INVENTOR. WILLmM F1 GROENE IDMMSJQSW ic,.]I.

ATTORNEY.

Dec. 6, 1938.

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ORBITAL LATHE 15' Sheets-Sheet 3 Filed Jan. 26, 1937 FREE.

INVENTOR. W/Lunn R Gnome ATTORNEY.

W. F; GROENE Dec. 6, 1938.

ORBITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 4 mmm ; INVENTOR.

WILL Fm F1 Gene/vs 1Q $S\ .,95.M

ATTORNEY.

. 6, 1938. w. F. GROENE ORBITAL LATHE File d- Jan. 26, 1937 15- Sheets-Sheet 5 IN VENTOR WILL/HM F3 Gnosus ATTORNEY.

W. F. GROENE- ORBITAL LATHE 1s Shets-Sheet 6 Filed Jan. 26, 1937 L 0E M M 2 m: m m m L m: M W /a/1///-/ r/ M/// fT// W/ f//; hz7 rf Q W PM "H a m I m A i a. a l h v M i M e s U L w *3 NM a a m M 0 6 an IQ.m Q. o hum Mb h n@ hm mi $5 I m6 .mm m. W m@ .2 H \E N NI T T HH AR ow mm h 5 m & WW t G E .R :N 2N 3 wr aw 5 9 3w 2:

W. F. GROENE Dec. 6,19%.

ORB ITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 7 IN\/ ENTOR. WILLIHM RGR ENE- ATTORNEY.

W. F. GROENE ORBITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 8 INVENTOR. WILL/HM Ff GROENE ATTORNEY.

W. F. GROENE ORBITAL LATHE Dec. 6, 1938.

15 Sheets-Sheet 9 Filed Jan. 26, 1937 Dec. 6, 1938. w. F. GROENE ORBITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 10 3mm W/u/nn-F! GROENE 15 Sheets-Sheet 11 mam bo a WILL/HM F. GROENE W. F. GROENE ORB ITAL LATHE Filed Jan. 26, 1957 EMMA Dec. 6, 1938.

Dec. 6, 1938.

w. F. GROENE 213%,964

ORBITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 12 E INVENTOR.

H/tL/IWEGROEIIE ATTORNEY.

W. F. GROENE- Dec. 6, 1938.

ORBITAL LATHE Filed Jan. 25, 1957 15 Sheets-Sheet 13 F7E 'TXXYI w, WW5

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INCH l START I III II IIIII Dec. 6, 1938. w. F. GROENE 2,138,964

ORBITAL LATHE Filed Jan. 26, 1957 15 Sheets-Sheet 14 F Y INVENTOR. MLL/nnFmoe/vs MBLWM AM ATTORNEY.

W. F. GROENE Dec. e, 1938.

ORB ITAL LATHE Filed Jan. 26, 1937 15 Sheets-Sheet 15 Z] wuc/wfop wlLL/rmff GROENE enema n...- e', 1938.

UNITED STATES;

"PATENT" OFFICE OR-BITALLATHE William F. Groene, Cincinnati, Ohio, assignor to R. K. Le Blond Machine Tool Company, Cincinnati, Ohio, a corporation of Delaware Application January 26, 1937, Serial N6. 122,349; 5

ciated surfaces on a plurality of crankshafts in a single operation.

My invention consists in certain new and useful character set forth in my Patent 1,934,530 issued November 7, 1933, an object of my invention being to provide means in such lathes whereby the faces of the webs adjacent a plurality of crank pins of a plurality of crankshafts may be simultaneously checked in a single operation.

Another object is to provide means whereby the diameters and 'fillets of a plurality of crank pins of a plurality of crankshafts may be turned and faced simultaneously in a single operation.

Another object is to arrange the machine so that rough turning operations may be undertaken on some of the spindles while finishing operations are simultaneouslybeing undertaken on others of said spindles.

Another object is to arrange such a multiple spindle lathe so that some of the spindles are adapted for checking the faces of the webs adjacent crank pins while othersof the spindles are adapted to turn the pins on a plurality of crankshafts simultaneously.

A still further object is to arrange certain of the spindles for completely finishing parts of the webs and adjacent crank pins while others of said spindles are adapted for simultaneously-finishing other portions of said webs and adjacent crank pins.

It is also my intention to provide a rotary cam means for actuating the orbitally moving cutting tools in coarse feed, fine feed, and dwell and hydraulic means for rotating said cam means to rapid traverse or feeding speeds in either direction.

In connection with the hydraulically operated I have also improved and greatly simplified the method of connecting the linkage connection bev tween the upper master crankshaft and the tool carrying units.

:I have further provided a unique combined 5 manual and automatic means 'for controlling the rapid traverse of the cuttingtools relative to the work pieces whereby the rapid traverse may be actuated manually independent of and without effecting the normal automatic means for causing 10 said rapid traverse movements.

A furtherobject is to provide means for feeding cutting tools relative to a plurality of crank pins of a plurality of crankshafts simultaneously in rapid traverse, coarse feed, fine feed and dwell 15 to cheek the faces of .webs adjacent crank pins and to turn said crank pins in a single operation.

' A further object is to feed cutting tools relative to a plurality of crank pins of a plurality of crankshafts simultaneously in rapid. traverse and 2 coarse feed to cheek the faces'of webs adjacent said crank pins in a single operation.

A further object is to feed cutting tools. relative to a plurality of crank pins 'of 'a plurality of crankshafts simultaneously in rapid traverse 26 and fine feed to turn s'ald' crank pins in a single operation.

And still a further object is to feed cutting toolsrelative to a plurality of crank pins of a plurality of crankshafts simultaneously in rapid 3 traverse, coarse feed, fine feed, and dwell whereby certain of said tools do cheekingoperations on 'some of webs adjacent said crank pins while others of said tools do turning on others of said crank pins in a single operation. 35 I also provide a safety device in connection with the manual means for rotating the spindle driving mechanism whereby the power means for driving the spindles is rendered ineffective when the spindles are being actuated manually. 40

A unique arrangement is provided for directly lubricating the working parts of thelathe from the pressure fluid system for feeding the cutting tools.

I'further provide means'for maintaining the 45 feeding cradle in contact with the feeding cams to eliminate cutting vibration in the cutting tools and to assure positive return of the tool carrier units at the end of the cutting cycle.

I-also have arranged the machine whereby the 50 spindle speeds are automatically controlled by the relative position of the work-and tools and the nature of the work being done by the tools.

' One arrangement for turning the crank pins on a plurality of crankshafts simultaneously is to cause the spindles to rotate automatically at relatively high speed until the tools have substantially finished their turning operation and then automatically cause the spindles to rotate at relatively slow rate as the tools enter the dwell period to precisely finish the pin without chatter or vibration and the resultant defects in the work surface.

Another arrangement when doing cheeking and pin turning operations simultaneously on the pins of a plurality of crankshafts is to cause the spindles to rotate relatively slowly at the beginning of the cheeking operation and to automatically increase in speed toward the end of the cheeking cut, to remain in high speed while the pins are being turned, and to drop automatically back to relatively slow speed as the cutting tools enter the dwellperiod for sizing the pins.

Other features of my invention will be pointed out in the following description of the drawings in which:-

Figure I is a front perspective view of a multiple spindle orbital crankshaft lathe adapted to utilize the principles of my invention.

Figure II is an enlarged perspective view of a portion of the front of the machine showing crankshafts chucked on the work spindles for machining operations on the cheeks of the webs adjacent the crank pins.

Figure III is an enlarged perspective view of a portion of the front of the machine showing crankshafts chucked on the work spindles for turning the diameters and filletspf the crank pins.

Figure IV shows a portion of a crankshaft with a tool applied to machine the cheek of a web adjacent a crank pin.

Figure IVa shows a portion of a crankshaft with a tool applied to turning the diameter and fillets of a crank pin adjacent the machined web of Figure IV.

Figure V shows a portion of a crankshaft with tools applied to machine the cheeks of the webs adjacent a crank pin.

Figure Va shows a portion of a crankshaft with a tool applied to turning the diameter and fillets of a crank pin adjacent the, machined webs of Figure V.

Figure VI shows a portion of a crankshaft with a tool adapted to cheek the face of a web adjacent a crank pin and to turn the diameter of the crank pin.

Figure VIa shows a portion of a crankshaft with tools applied to face and neck the fillets of' the crank pin of Figure VI.

Figure VII shows a portion of a crankshaft with tools applied to cheek the faces of the webs adjacent a crank pin' and to turn a portion of the diameter of the crank pin.

Figure VIIa shows a portion of a crankshaft with a tool applied to turning the unfinished diameter and fillets of a crank pin adjacent the machined webs of Figure VIII.

Figure VIII is a perspective view of the rear of the machine of Figure I particularly showing the arrangement of the tool carriers, the driving gears for the master crankshafts and spindles, and the hydraulic feeding system.

Figure DI is a vertical transverse section on the line IX-IX of Figures 111 and IXa particularly showing the left hand steady rest unit and the support bearing for the intermediate bearings of the upper master crankshaft.

Figure IXa is a rear perspective view of the feeding cradle particularly indicating the integral structure, the mounting arrangement for the upper master crankshaft, and the lubricant distributing manifold.

Figure X is a vertical transverse section on the line X--X of Figures III and IXa. particularly showing orbitally moving tool carrier unit.

Figure XI is a vertical transverse section on the line XI-XI of Figures I, XIII, and XXIII particularly showing the arrangement of the limit switch for changing speeds for the work spindles.

Figure XII is an enlarged front elevation of the-upper portion of the left hand housing shown in Figures I and mu.

Figure XIII is a vertical transverse section on the line IHIIX11I of Figure III and IXa, partly broken away, to more clearly show the mechanism for actuating the feeding cams.

Figure XIV is a front elevation of the combined manual and automatic rapid traverse control mechanism located at the upper left hand end of the left hand housing.

Figure XV is an end elevation of the mechanism shown in Figure XV.

Figure XVI is diagrammatic illustration of various modes of feeding cheeking tools in the lathe.

Figure XVII is a right hand end elevation partly in section on line XVII-XV1I of the upper portion of the right hand housing particularly showing the variable speed control device for the spindles.

Figure XVIII is a plan view of the top front portion of the right hand housing showing the mechanism of Figure XVII.

Figure XIX is a rear view of the outer end of the main driving motor showing the safety device in connection with the manual means for rotating said motor.

Figure XIXa is a plan view of the top of the feeding cradle shown in lXa.

Figure XX is an end elevation of the motor and mechanism shown in Figure XIX.

Figure XXI is a right hand end elevation of a portion of the machine showing a part of the lower spindle gear and cam mechanism for operating the limit switch for dynamic braking spindle rotation.

Figure XXII is a plan view of the mechanism shown in Figure )QCI.

Figure IQCIII is an nlarged front elevation of the upper portion of the lathe with covers removed particularly showing the lubricant distributing system for the working parts of the lathe.

Figure XXIV is a section through the control valve for the lubricant distributing system shown in Figure XXIII.

Figure XXV is a diagrammatic layout of the hydraulic operating and control mechanism for the lathe.

Figure IDIVI is a wiring diagram of the electrical equipmen-i utilized to operate the spindle drive motor and accessories, wherein the spindles are operated at a high speed and a low speed.

Figure XXVII is a wiring diagram of the electrical equipment utilized to operate the spindle drive motor and accessories, wherein the spindles are operated at three different speeds.

Figure IDIVIII is a wiring diagram of the electrical equipment utilized to operate the spindle drive motor and accessories, wherein the spindles are operated at variable speed.

The general arrangement of the machine of the exemplary disclosure is substantially like that shown in my earlier Patent Number 1,934,530 excepting that in this disclosure only two work spindles are shown whereas in said patent three work spindles are. employed. The machine comprises a rectangular base I to which are fixed the left hand housing 2 and the right hand housing 3 by means of suitable bolts 4. Between the housings 2 and 3 the base i is provided with a large chip compartment 5 which has an apron 6 at the front of the machine to prevent coolant and chips from escaping on the floor and an access opening 1 at the rear whereby chips may be removed without interfering with the operation of the lathe. The floor 8 of the chip compartment is provided with the usual drainage screens 9 to drain the coolant from the chips into the coolant chamber ill from which iting upon the number of-lntermediate line bearings present on the crankshaft being machined. For example, in Figures I and III, I show the machine applied to a'six-throw four-line-bearing crankshaft l3 having the stub end l4 and its associated line bearing IS; the flange end l6 and its associated line bearing H; the intermediate line bearings l8 and I9; and crank pins 2|, 22,

23, 24, 25, and 26. Two steady rest units 26 are therefore required to support the intermediate line bearings I8 and iii of the crankshaft i3.

Another example is shown in Figure Il wherein the machine is adapted to an eight-throw fiveline bearing crankshaft 21 having the stub end 28 and its associated line bearing 29: the flange end 30 and its associated line bearing 3|; the

intermediate line bearings 32, 33, and 34; and crank pins 35, 36, 31, 38, 38, 40, 4|, and42. Three steady rest units 26v are thereforerequired, in,

this instance, to support the intermediate line bearings 32, 33, and 34.

Noting particularly Figure IX,the .steady rest units 26 are secured to floor 8 of the chip compartment by bolts 43 and. to the rib 44. at the rear of the base by bolts 45. The units 26 are also securely fastened to the front tie bar II by bolts 46 and to the rear tie bar by bolts 41.

The. crankshafts, as for example the crankshafts |3 or- 21, are chucked and driven from their ends by means of chucks 48, preferably of a character shown in my Patent Re 19,730 and 2,030,142 which are carried on appropriate spindles 49 rotatably mounted in each of the housings 2 and 3. On the steady rest units are provided steady rests 50 adapted to engage and journal the intermediate line bearings of the crankshafts, preferably of a character as set forth in my Patents 1,906,577 and 1,934,530 and in my application Serial No. 108,038 filed October 28, 1936.

Feeding cradle At the rear of the machine is journaled the lower master crankshaft 5| in suitable bearings 52 in each housing 2 and 3 and also in bearings 53 in each steady rest unit 26, the crankshaft 5| being properly held in place in bearings 52 by bolts 54 passing through caps 55 and in bearings 53 by bolts 56- passing through caps 51. An upper master crankshaft 58 is journaled in appropriate bearings 59 (Figures V111 and XIII) in the feeding cradle 60 and is held in place in said bearings by bolts 6| passing through caps 62. The cradle 60 has downwardly extending pivot arms 63 passing in slots 64 formed in each of the housings 2 and 3 and having their lower ends 63a pivotally mounted about the axis of rotation of the lower master crankshaft 5|, preferably about the periphery of the bearings 52.

The cradle 60 has a roller 65 at each end rotatably mounted on a suitable stud 66 fixed in the cradle 60 which contacts the periphery of the rotary feed cams 61 located in the slots 64 in each housing 2 and 3 and fixed on the cam shaft 68 which shaft is journaled in appropriate bearings 69in each housing 2 and 3. It can thus be seen that upon proper rotation of the cam shaft 68 and cams 61 the cradle 60 may be rocked around its pivotal mounting about the bearings 52 to thereby move the upper master crankshaft upwardly and rearwardly or vice versa.

This feeding cradle 60 has been greatly improved and its structure altered Over that of the arrangement of swinging the upper master crankshaft in my Patent 1,934,530 in that I have provided a massive structural section 10 comprising the ribs 10a and web sections 10b formed integral with pivot arms 63 thereby securely tying said arms together and cause said arms 63 to swing in unison upon operation of the cams 61. Thus any twisting and distortion which might be caused in the master crankshaft 58 in the former structure of Patent 1,934,530 is fully eliminated. Also it is to be noted that in this arrangement the intermediate line bearings 1| of the master crankshaft 58 are rigidly supported in appropriate bearings in the web sections 12 formed integral with the web sections 10b of the cradle 60 and held in said bearings by means of the usual bolts 13 passing through the caps 14.

The tool carrier-units 15, Figure X, carrying the tool holders 16 and tools T for cutting operations on the crank pins of the work pieces are journaled on the crank pins 18 of the lower master crankshaft 5| and connected to the upper master crankshaft 58 by means of the linkage connection 19 which connection is appropriately journaled about the crank pins of said upper master crankshaft 58 and is attached to the tool carrier units 15 by a unique pivotal connection comprising a partial cylindrical socket or bearing 8| formed in said unitsinto which is nicely fitted a cylindrical integral boss 82 of the linkage connection 19. The advantage of this construction -is that fewer parts are required than in the former constructions used for this purpose and also permits the use of the full width of both the tool carrier units and the linkage connection at the point of juncture thereby giving much greater rigidity and strength at this vital part of the machine. By this arrangement the tool carrier units 15 may be swung about the crank pins 18 of the lower master crankshaft 5| upon swinging of the cradle 60 in a; manner already described'to feed the cutting tools T to and from the crank pins of the work pieces.

Unique mechanism is provided to damr out vibration in the feeding cradle and tool carrier units during cutting operations and to elfect positive return of the cradle after said operations are completed comprising a resilient means to yieldingly urge the cardle 60 with its rollers 65 at all times against theperipheral-cams 61. For expivotally mounted by a suitable pin 84 fixed to a boss 85 formed on the arms 63 of the cradle 60 in which is mounted a reciprocatable piston 86 connected to a piston rod 8'! which in turn is pivotally mounted by a suitable pin 88 in the upstanding integral arm 89 of each of the housings 2 and 3. Fluid pressure delivered through the pipe 90 is at all times maintained in chamber 9I, leakage past the piston 86 being drained off through the pipe 92 leading from chamber 93. Suflicient travel allowed the piston 86 in cylinder 83 and the pivotal connections about pins 84 and 88 permit the continuous application of pressure to force the cradle toward the cams 61 throughout its full range of swinging.

Driving mechanism for spindles and master crankshafts Noting particularly Figures VIII and XIII, on the ends of the lower master crankshaft 5I projecting beyond the bearings 52 of the housings 2 and 3 are fixed the gears 94 and 95 each gear being adapted to drive idler gears 96 rotatably mounted on studs 91 fixed in the outside faces of the housings 2 and 3 and which idler gears 96 in turn engage gears 98 of identical size as the gears 94 and 95 mounted on the work spindles 49. The gear 94 also is adapted to drive an idler gear 99 rotatably mounted on a stud I fixed in an arm 63 (Figure IXa) of the cradle 60 which idler gear in turn is adapted to drive the gear IOI, of identical size of the gear 94, fixedon an end of the upper master crankshaft 58. Thus it can be seen that rotation of the gears 94 and 95 and lower master crankshaft will cause similar synchronous rotation of the work spindles 49 and the upper master crankshaft 58. The above mechanism is actuated by means of the usual driving motor I02 mounted on the bracket I03 fixed to the right hand end of the base I, power being transmitted through the usual reduction gearing, preferably to the gear 94.

On the outer end of the motor shaft I04, opposite the driving pinion end, is fixed a capstan head I05, Figures 1, XIX, and XX, which has spaced radially extending holes I06 formed in its periphery whereby a bar may be inserted in any of said holes to provide manual means for rotating the motor I 02 and thereby the spindles and master crankshafts. It is to be noted that in the event the operator inadvertently left the bar in one of the holes I06 of the capstan head I05 and started the motor I02 serious damage would result to the motor and possible injury to the operator. In order to avoid such an occurrence I have provided a novel safety device in connection with the capstan head I05 whereby the bar must be removed from the head beforethe motor I 02 can be rendered operative.

This safety device comprises a U shaped cover I01 which is hinged at I08 to a bracket I09 attached to the motor I02 and is thereby adapted to be swung over the capstan head I05 or to be swung away from said disc to a position indicated at I0Ia. Mounted on the bracket I09 is a limit switch IIO which controls appropriate relays for connecting or disconnecting the main source of power from the motor I02 in the usual manner. The limit switch IIO has the control arm III and roller II2 which are actuated by the cover I01 when in position I 01a whereby power is disconnected from the motor I02 and at which time a bar may be applied to the capstan head I05. Before the motor I02 can be rendered operative the cover I01 must be swung over the.

capstan head I05 to relieve the limit switch IIO to connect power to the motor which forces the operator to remove the bar from the capstan head to accomplish this'result.

Feed drive mechanism Noting particularly Figure XIII, the means for actuating the cams 61 fixed on the cam shaft 68 comprises the usual hydraulic cylinder II3 vertically mounted on the front of the base I directly beneath the housing '2. In the cylinder is a reciprocatable piston II4 to which is connected the upwardly extending piston rod II5 which in turn is connected to the vertically reciprocatable rack II6 slidably mounted in appropriate guideways II'I found in the front face of the housing 2. A stop block II 8 secured to the upper end of the rack '6 by screws H9 is adapted to abut against the top surface I20 (Figure XII) of the housing 2 to limit downward travel of said rack H6 and piston I I4, so that the piston does not bottom in said cylinder upon return of the tool to starting position.

Rack teeth I2I cut on the rearward face of the rack II6 engage the idler gear I22 rotatably mounted on the stud I23 fixed in the housing 2 which idler in turn engages a gear segment I24 formed on the cam 61 located in the slot 64 of housing 2, the idler I22 likewise being located insaid slot 64 of housing 2.

It can thus be seen that upon reciprocation of rack II6 by the piston II4, idler gear I22 will be rotated and will cause rotation of cam 61 located in housing 2 and through cam shaft 68 the simultaneous rotation of cam 61 in housing 3 for swinging the cradle 60 and actuating the cutting tools TI as described.

Hydraulic operating and control mechanism Noting particularly Figure XXV, the source of power for operating the hydraulic system is derived from the electric motor I25 mounted on the bracket I26 on the left hand side of the base I (Figure VIII) which drives the low-pressure high-volume fluid pressure pump I21 and the high-pressure low-volume fluid pressure pump I28 which pump fluid from the storage tank I29 through line I30. To the exhaust port of pump I2! is applied a relief valve I3I and to the exhaust port of pump I28 is applied a relief valve I 32, both of said valves being connected into the main discharge line I 33 and having their discharge ficws emptying into the drain line I34 by appropriate arrangements in the valve housing I 35. The relief valve I32 is set at a relatively higher pressure than relief valve I3I. Connected to the line I33 is a pressure regulating valve I36 which at all times maintains a substantial minimum pressure in the line I33 at a pressure below the pressure setting of either of the relief valves I3I and I32. Thus pressure is at all times properlymaintained in line 90 to render the vibration dampening mechanism comprising the cylinder 83 and its accessories effective. The discharge port I3'I of valve I36 is connected through line I38 to the inlet port I39 of the main control valve I40. The pressure reducing valve MI is connected to the valve I36 and thereby directly to the line I33 through line I42 and is set for the same pressure as valve I36 whereby fluid pressure is at all times supplied to .line I43 at a pressure equal to the pressure settings of valves I36 and MI. A line I44 connecting with line I43 conducts the fluid pressure to the control valve I45 for controlling the clamping mechanism for the chucks 48 on the upper spindle and to the control valve I46 for the chuclm 48 on the lower spindle.

In the operation of the lathe the crankshafts are placed in the chucking devices and the steady rests 50 closed over the line bearings. The chucking control valves I45 and I46 are then manipulated so that fluid pressure from line I44 is transmitted through lines I41 to the chambers I48 of the chucking cylinders I49 of the work spindles 49 to thereby actuate the gripping mechanism of chucks to hold the work therein, the

chambers I50 of said cylinders I49 being connected through line II through the valves I45 and I46 to the drain line I52 whereby fluid may escape therefrom and return to the tank I29.

After having thus properly chucked the work in the lathe the main drive motor I02 is set in motion for rotating the spindles 49 and master crankshafts 5i and 58 by actuating the starting handle I53 of the master starting and inching switch I54 (Figures I, IX, X, and XIII). The.

feed control handle I55 is then moved to the left (Figures I and XXV)'to forward feed position to actuate the valve I40 through suitable linkage I56 and plunger I51 so that fluid pressure is caused to flow from line I38 into line I58 communicating with the chamber I 59 of cylinder II3 raising the piston I I4 and thereby upwardly moving the rack II6 to rotate the feeding cams 61 to move the cutting tools T toward the work as described. A spring I60 connected to the cam plate arm 'I6I of the lever I55 normally yieldingly urges the lever I55 to the right. On the rack H6 is fixed a cam plate I62 which travels upward with the rack when the lever I55 is moved to the left, the arm- I6I of said lever I55 having a pin I63 engaging the cam slots of said cam plate. It can thus be seen that upon moving the lever I55 to the left the pin I63 will be brought in alignment with the forward feed cam slot I64 in cam plate I62 and will be held therein upon upward movement of the rack I I6 to thereby relieve the operator of the necessity of holding said lever I55 to maintain feeding motion.

The rate of upward movement of piston. II4 under the influence of fluid pressure I59 is determined by the rate of escape of fluid permitted from chamber I65 of cylinder II3. When itis desired to move the piston I I4 upward at forward feeding rates fluid is allowed to escape from chamber I65 through lines'I66 and I61 to the ad- .justable metering or feed rate control valve I68 from which valve I68 the fluid escapes at a relatively slow rate through line I69; into valve I40, and then through the drain line I to discharge into the tank I29. The rapid traverse control valve "I is connected to the lines I66 and I61 through line I12 and through line I13 to the line I69. The rapid traverse valve. III is so constructed that its plunger I14 is normally urged upward (Figure XXV) to prevent flow of fluid from lines I12 to I13 and to at alltimes permit free flow of fluid from lines I13 to I12.

During forward feeding movements the rapid traverse valve III has its plunger I14 upwardly extended thereby preventing flow from line I12 to- I13 thus closing off line I12. The metering valve I68 causes back pressure to be built up in The opening of the low pressure relief valve I3I allows the flow from the low-pressure high volume pump I21 to escape through the drain line I34 so that this pump is ineifective to actuate the piston H4. The high-pressure low-volume pump I28 exhausts all surplus fluid not needed in chamber I 59 for feeding movement past relief valve I3I and valve I36 thus actuating the piston H4 at feeding rates under high pressure to give a smooth and powerful feed to the cutting tools T.

When it is desired to actuate the cutting tools in rapid traverse toward the work the plunger I14 of the rapid traverse valve I1I is depressed connecting line I12 to line I13 whereby fluid is allowed to freely escape from chamber I65 of cylinder II3-through lines I66 and I12, valve I1I, lines I13 and I69, valve I40, and line I10 into the tank I29. Pressure under these circumstances is substantially removed from chamber I65, so that the-only pressure in chamber I59 I 4| pressure in lines I 38 and I43 would drop below a safe operating pressure for the cylinder 63 and the chucking cylinders I49. Since the pressure in chamber I59 is thus below the setting of valve I36 in forward rapid traverse and therefore below the settings of valves I3I and I32, the pumps I21 and I 28 therefore do not discharge through their respective relief valves I3I and I32 but transmit both of their flows through valve I36 to chamber I59 giving ample volume of flow at relatively low pressure to rapidly raise the piston H4 at rapid traverse rates.

As the cutting tools reach the end of their dwell period the rack H6 and cam plate I62 have traveled upward to a point where the pin I63 rides oil the edge I of cam slot I 64 and the arm I6I and its lever I55 are drawn to the right upon the valve I40 is shifted through the linkage I56 and plunger I 51 so that the fluid may flow freely from line I38 through lines I69 and I13, rapid traverse. valve "I, and lines I12 and I66 into chamber I65 of cylinder H3. The chamber I59 is then connected through line I58, valve I40, and line I10 to the tank I29 relieving substantially all back pressure from chamber I59. Thus as inthe case of forward rapid traverse both pumps I21 and I28 deliver their flow through valve I36 to chamber I65 supplying ample volume at low pressure to return the piston- II4 downwardly at rapid traverse speed. As the cam plate is returned downward the angular portion I11a of cam slot I11 engages pin I63 and thereby moves the plunger I51 to an intermediate or neutral. position thereby discontinuing further rapid traverse return pressure in chamber I 65 and to hold the .tools T in retracted position.

In connection with the forward rapid traverse movement I have provided a novel arrangement whereby said rapid traverse is rendered operative or inoperative at the proper time both manually and automatically as desired. The mechanism is particularly shown in Figures I, XIV, XV, and XXV, and comprises a vertically arranged rod I18 which is connected at its lower' end to the plunger I14 of the rapid traverse valve HI and connected at its upper end to the yoke I19 which member has a slot I60 extending axially of rod I18 and nicely fitting about the bearing portion I8I of the end of the cam shaft 

